fix(click): account for transformed iframes (#18926)

- Properly convert coordinates for iframes with non-zero borders.
- IFrames that have `transform` anywhere in the ancestors skip
`hitPoint`-based check because we cannot reliably translate the viewport
point into frame document's coordinates.

Fixes #18245.

packages/playwright-core/src/server/dom.ts

@@ -869,16 +869,23 @@ export class ElementHandle<T extends Node = Node> extends js.JSHandle<T> {
     return result;
   }
 
-  async _checkFrameIsHitTarget(point: types.Point): Promise<{ framePoint: types.Point } | 'error:notconnected' | { hitTargetDescription: string }> {
+  async _checkFrameIsHitTarget(point: types.Point): Promise<{ framePoint: types.Point | undefined } | 'error:notconnected' | { hitTargetDescription: string }> {
     let frame = this._frame;
     const data: { frame: frames.Frame, frameElement: ElementHandle<Element> | null, pointInFrame: types.Point }[] = [];
     while (frame.parentFrame()) {
       const frameElement = await frame.frameElement() as ElementHandle<Element>;
       const box = await frameElement.boundingBox();
-      if (!box)
+      const style = await frameElement.evaluateInUtility(([injected, iframe]) => injected.describeIFrameStyle(iframe), {}).catch(e => 'error:notconnected' as const);
+      if (!box || style === 'error:notconnected')
         return 'error:notconnected';
+      if (style === 'transformed') {
+        // We cannot translate coordinates when iframe has any transform applied.
+        // The best we can do right now is to skip the hitPoint check,
+        // and solely rely on the event interceptor.
+        return { framePoint: undefined };
+      }
       // Translate from viewport coordinates to frame coordinates.
-      const pointInFrame = { x: point.x - box.x, y: point.y - box.y };
+      const pointInFrame = { x: point.x - box.x - style.borderLeft, y: point.y - box.y - style.borderTop };
       data.push({ frame, frameElement, pointInFrame });
       frame = frame.parentFrame()!;
     }

packages/playwright-core/src/server/injected/injectedScript.ts

@@ -507,6 +507,18 @@ export class InjectedScript {
     return { left: parseInt(style.borderLeftWidth || '', 10), top: parseInt(style.borderTopWidth || '', 10) };
   }
 
+  describeIFrameStyle(iframe: Element): 'error:notconnected' | 'transformed' | { borderLeft: number, borderTop: number } {
+    if (!iframe.ownerDocument || !iframe.ownerDocument.defaultView)
+      return 'error:notconnected';
+    const defaultView = iframe.ownerDocument.defaultView;
+    for (let e: Element | undefined = iframe; e; e = parentElementOrShadowHost(e)) {
+      if (defaultView.getComputedStyle(e).transform !== 'none')
+        return 'transformed';
+    }
+    const iframeStyle = defaultView.getComputedStyle(iframe);
+    return { borderLeft: parseInt(iframeStyle.borderLeftWidth || '', 10), borderTop: parseInt(iframeStyle.borderTopWidth || '', 10) };
+  }
+
   retarget(node: Node, behavior: 'none' | 'follow-label' | 'no-follow-label' | 'button-link'): Element | null {
     let element = node.nodeType === Node.ELEMENT_NODE ? node as Element : node.parentElement;
     if (!element)
@@ -901,16 +913,18 @@ export class InjectedScript {
   //     2k. (injected) Event interceptor is removed.
   //     2l. All navigations triggered between 2g-2k are awaited to be either committed or canceled.
   //     2m. If failed, wait for increasing amount of time before the next retry.
-  setupHitTargetInterceptor(node: Node, action: 'hover' | 'tap' | 'mouse' | 'drag', hitPoint: { x: number, y: number }, blockAllEvents: boolean): HitTargetInterceptionResult | 'error:notconnected' | string /* hitTargetDescription */ {
+  setupHitTargetInterceptor(node: Node, action: 'hover' | 'tap' | 'mouse' | 'drag', hitPoint: { x: number, y: number } | undefined, blockAllEvents: boolean): HitTargetInterceptionResult | 'error:notconnected' | string /* hitTargetDescription */ {
     const element = this.retarget(node, 'button-link');
     if (!element || !element.isConnected)
       return 'error:notconnected';
 
-    // First do a preliminary check, to reduce the possibility of some iframe
-    // intercepting the action.
-    const preliminaryResult = this.expectHitTarget(hitPoint, element);
-    if (preliminaryResult !== 'done')
-      return preliminaryResult.hitTargetDescription;
+    if (hitPoint) {
+      // First do a preliminary check, to reduce the possibility of some iframe
+      // intercepting the action.
+      const preliminaryResult = this.expectHitTarget(hitPoint, element);
+      if (preliminaryResult !== 'done')
+        return preliminaryResult.hitTargetDescription;
+    }
 
     // When dropping, the "element that is being dragged" often stays under the cursor,
     // so hit target check at the moment we receive mousedown does not work -

tests/library/hit-target.spec.ts

@@ -362,3 +362,35 @@ it('should detect overlay from another shadow root', async ({ page, server }) =>
   const error = await page.locator('#container1 >> text=click me').click({ timeout: 2000 }).catch(e => e);
   expect(error.message).toContain(`<div id="container2"></div> intercepts pointer events`);
 });
+
+it('should detect overlayed element in a transformed iframe', async ({ page }) => {
+  await page.setContent(`
+    <style>
+      body, html, iframe { margin: 0; padding: 0; border: none; }
+      iframe {
+        border: 4px solid black;
+        background: gray;
+        margin-left: 33px;
+        margin-top: 24px;
+        width: 400px;
+        height: 400px;
+        transform: scale(1.2);
+      }
+    </style>
+    <iframe srcdoc="
+      <style>
+        body, html { margin: 0; padding: 0; }
+        div { margin-left: 10px; margin-top: 20px; width: 2px; height: 2px; }
+        section { position: absolute; top: 0; left: 0; bottom: 0; right: 0; }
+      </style>
+      <div>Target</div>
+      <section>Overlay</section>
+      <script>
+        document.querySelector('div').addEventListener('click', () => window.top._clicked = true);
+      </script>
+    "></iframe>
+  `);
+  const locator = page.frameLocator('iframe').locator('div');
+  const error = await locator.click({ timeout: 2000 }).catch(e => e);
+  expect(error.message).toContain('<section>Overlay</section> intercepts pointer events');
+});

tests/page/page-click.spec.ts

@@ -32,7 +32,7 @@ it('should click the button @smoke', async ({ page, server }) => {
 it('should click button inside frameset', async ({ page, server }) => {
   await page.goto(server.PREFIX + '/frames/frameset.html');
   const frameElement = await page.$('frame');
-  await frameElement.evaluate(frame => frame.src = '/input/button.html');
+  await frameElement.evaluate((frame: HTMLFrameElement) => frame.src = '/input/button.html');
   const frame = await frameElement.contentFrame();
   await frame.click('button');
   expect(await frame.evaluate('result')).toBe('Clicked');
@@ -886,3 +886,126 @@ it('should climb up to a [role=link]', async ({ page }) => {
   await page.click('#inner');
   expect(await page.evaluate('__CLICKED')).toBe(true);
 });
+
+it('should click in an iframe with border', async ({ page }) => {
+  await page.setContent(`
+    <style>
+      body, html, iframe { margin: 0; padding: 0; border: none; box-sizing: border-box; }
+      iframe { border: 4px solid black; background: gray; margin-left: 33px; margin-top: 24px; width: 400px; height: 400px; }
+    </style>
+    <iframe srcdoc="
+      <style>
+        body, html { margin: 0; padding: 0; }
+        div { margin-left: 10px; margin-top: 20px; width: 2px; height: 2px; }
+      </style>
+      <div>Target</div>
+      <script>
+        document.querySelector('div').addEventListener('click', () => window.top._clicked = true);
+      </script>
+    "></iframe>
+  `);
+  const locator = page.frameLocator('iframe').locator('div');
+  await locator.click();
+  expect(await page.evaluate('window._clicked')).toBe(true);
+});
+
+it('should click in an iframe with border 2', async ({ page }) => {
+  await page.setContent(`
+    <style>
+      body, html, iframe { margin: 0; padding: 0; border: none; }
+      iframe { border: 4px solid black; background: gray; margin-left: 33px; margin-top: 24px; width: 400px; height: 400px; }
+    </style>
+    <iframe srcdoc="
+      <style>
+        body, html { margin: 0; padding: 0; }
+        div { margin-left: 10px; margin-top: 20px; width: 2px; height: 2px; }
+      </style>
+      <div>Target</div>
+      <script>
+        document.querySelector('div').addEventListener('click', () => window.top._clicked = true);
+      </script>
+    "></iframe>
+  `);
+  const locator = page.frameLocator('iframe').locator('div');
+  await locator.click();
+  expect(await page.evaluate('window._clicked')).toBe(true);
+});
+
+it('should click in a transformed iframe', async ({ page }) => {
+  await page.setContent(`
+    <style>
+      body, html, iframe { margin: 0; padding: 0; border: none; }
+      iframe {
+        border: 4px solid black;
+        background: gray;
+        margin-left: 33px;
+        margin-top: 24px;
+        width: 400px;
+        height: 400px;
+        transform: translate(100px, 100px) scale(1.2) rotate3d(1, 1, 1, 25deg);
+      }
+    </style>
+    <iframe srcdoc="
+      <style>
+        body, html { margin: 0; padding: 0; }
+        div { margin-left: 10px; margin-top: 20px; width: 2px; height: 2px; }
+      </style>
+      <div>Target</div>
+      <script>
+        document.querySelector('div').addEventListener('click', () => window.top._clicked = true);
+      </script>
+    "></iframe>
+  `);
+  const locator = page.frameLocator('iframe').locator('div');
+  await locator.click();
+  expect(await page.evaluate('window._clicked')).toBe(true);
+});
+
+it('should click in a transformed iframe with force', async ({ page }) => {
+  await page.setContent(`
+    <style>
+      body, html, iframe { margin: 0; padding: 0; border: none; }
+      iframe { background: gray; margin-left: 33px; margin-top: 24px; width: 400px; height: 400px; transform: translate(-40px, -40px) scale(0.8); }
+    </style>
+    <iframe srcdoc="
+      <style>
+        body, html { margin: 0; padding: 0; }
+        div { margin-left: 10px; margin-top: 20px; width: 2px; height: 2px; }
+      </style>
+      <div>Target</div>
+      <script>
+        document.querySelector('div').addEventListener('click', () => window.top._clicked = true);
+      </script>
+    "></iframe>
+  `);
+  const locator = page.frameLocator('iframe').locator('div');
+  await locator.click({ force: true });
+  expect(await page.evaluate('window._clicked')).toBe(true);
+});
+
+it('should click in a nested transformed iframe', async ({ page }) => {
+  await page.setContent(`
+    <style>
+      body, html, iframe { margin: 0; padding: 0; box-sizing: border-box; }
+      iframe { border: 1px solid black; background: gray; margin-left: 33px; margin-top: 24px; width: 400px; height: 400px; transform: scale(0.8); }
+    </style>
+    <iframe srcdoc="
+      <style>
+        body, html, iframe { margin: 0; padding: 0; box-sizing: border-box; }
+        iframe { border: 3px solid black; background: gray; margin-left: 18px; margin-top: 14px; width: 200px; height: 200px; transform: scale(0.7); }
+      </style>
+      <iframe srcdoc='
+        <style>
+          div { margin-left: 10px; margin-top: 20px; width: 2px; height: 2px; }
+        </style>
+        <div>Target</div>
+      '></iframe>
+    "></iframe>
+  `);
+  const locator = page.frameLocator('iframe').frameLocator('iframe').locator('div');
+  await locator.evaluate(div => {
+    div.addEventListener('click', () => window.top['_clicked'] = true);
+  });
+  await locator.click();
+  expect(await page.evaluate('window._clicked')).toBe(true);
+});